US3725731A - Self-scanning plasma display device with phosphor screen - Google Patents

Self-scanning plasma display device with phosphor screen Download PDF

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Publication number
US3725731A
US3725731A US00157971A US3725731DA US3725731A US 3725731 A US3725731 A US 3725731A US 00157971 A US00157971 A US 00157971A US 3725731D A US3725731D A US 3725731DA US 3725731 A US3725731 A US 3725731A
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Prior art keywords
display device
phosphor
elements
cathode
anode
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Expired - Lifetime
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US00157971A
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English (en)
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B Kazan
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International Business Machines Corp
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International Business Machines Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/38—Cold-cathode tubes
    • H01J17/48—Cold-cathode tubes with more than one cathode or anode, e.g. sequence-discharge tube, counting tube, dekatron
    • H01J17/49—Display panels, e.g. with crossed electrodes, e.g. making use of direct current
    • H01J17/498—Display panels, e.g. with crossed electrodes, e.g. making use of direct current with a gas discharge space and a post acceleration space for electrons

Definitions

  • ABSTRACT A display device having an inert gas-filled, transparent envelope, containing a set of parallel cathode elements an anode grid structure forming a venetian blind type structure and a glass support plate carrying a set of parallel conducting strips perpendicular to the plane of the parallel cathode strips and coated with a layer of ZnO phosphor. Light is emitted by the phosphor when one of the cathode elements is connected to a negative potential, the anode grid structure connected to a ground potential and one of the phosphor bearing conducting strips is connected to a low positive signal voltage. Color displays may be generated by applying a series of phosphors which generate different colors in an alternating fashion on the glass support plate.
  • the present invention relates to gas plasma display devices and more particularly to gas panel display devices in which a phosphor coating is used to produce light when bombarded by electrons.
  • gas plasma display devices are known poses of obtaining a grey scale rendition.
  • the prior art gas plasma display devices are known poses of obtaining a grey scale rendition.
  • light emission is binary in that the plasma is either ionized and emitting light or unionized and blanked.
  • a still further object of the present invention is to display grey scale information from a gas plasma phosphor display device.
  • a still further object of the present invention is to display color information from a gas plasma phosphor display device.
  • the present invention relates to a display device in which a gas plasma provides a source of electrons for energizing a phosphor layer to produce a visual display.
  • a set of cathode elements are contained in a gasfilled glass envelope, the cathode elements being connected in subsets to a plurality of pulse voltage sources, which control the application of potential to the cathode elements to cause a flow discharge to step in sequence from a first cathode element through all the cathode elements to a last cathode element in the display device.
  • a grid structure of anode elements is connected to a fixed potential to provide a field between the cathode elements and the anode to accelerate electrons to the light emitting phosphor layer and prevent ions from striking and damaging the phosphor layer.
  • the light emitting phosphor is placed on a transparent carrier, such as glass, which surface is provided with a series of parallel transparent conductors each of which is connected to one of a set of signal sources.
  • a transparent carrier such as glass
  • a display device constructed according to the present invention could be made on a large scale having a very large number of display elements in both the horizontal and vertical directions in contrast to display devices constructed according to the prior art which are limited by the cost of the high voltage driving circuitry to a relatively small number of elements.
  • FIG. 1 is a schematic view showing a preferred embodiment of the present gas plasma display invention.
  • FIG. 2 is an isometric view showing the preferred embodiment of the gas plasma display device from the front where the relative position of each element is more apparent.
  • FIG. 3 is a schematic diagram showing in block form they circuitry required to operate a display device constructed according to the present invention.
  • FIG. 4 is a timing diagram showing the relative times of the application of signals to the various elements of a display device constructed according to the present invention to produce a specific character display.
  • FIG. 5 is a representation of the characters generated by the signal shown in FIG. 4.
  • FIG. 1 A top cross section view of a display device for displaying alphanumeric information is shown schematically in FIG. 1, where a transparent envelope 102 (see also FIG. 2) contains each of the structural elements which will be identified below.
  • a group of sequentially excited cathode elements are mounted vertically adjacent to a back wall 106 of envelope 102.
  • a first of the cathode elements is designated as the starting cathode 108 and is located at the end of the row of sequentially excited cathode elements 1 10.
  • a grid or set of anode elements 1 14 is mounted vertically in front of cathode elements 1 10.
  • Each of the vertical anode elements 114 is mounted at an oblique angle to the path of electron flow from the plane of the cathode element 110 toward the front of envelope 102 (see FIG. 2).
  • a gas 116 fills the envelope 102 and when ionized provides a source of electrons.
  • a transparent support plate 126 is mounted between the row of anode elements 114 and the front plate 104 of envelope 102.
  • a set of closely spaced parallel transparent conducting strips 118, deposited on support plate 126 carries signal voltages to the addressed display column. These strips may be made of tin oxide.
  • a layer of phosphor 122 such as ZnO.
  • This structure forms the signal electrodes and the light-emitting phosphor layer within the glass envelope 102 of the display device 100.
  • display device 100 which may be schematically represented as a matrix of cathode elements 110 and signal elements 1 18 is connected to driving circuitry to supply necessary activation potentials to establish and transfer the glow discharge plasma which provides a source of electrons and the driving circuitry to provide the low voltage signal to attract the electrons from the plasma to a particular point on the phosphor 122.
  • Starting cathode element 108 is connected to start pulse generator 152 by lines 132.
  • Sequentially activated cathode elements 110 are connected in three groups to one of three lines from sequence control device 156 in the following manner:
  • Cathodes C1, C4, C7, C10, etc. are all connected in parallel to lines 134 which represent phase 1 of a threephase control sequence;
  • Cathodes C2, C5, C8, C11, etc. are all connected in parallel to lines 136 which are activated at phase 2 of a three-phase sequence control device 156;
  • Cathodes C3, C6, C9, C12, etc. are connected in parallel to lines 138, which are connected to the phase three output of sequence control device 156.
  • Each of the conducting elements 118 are connected to one of a group of signal control devices such as signal control device 162 or signal control device 172 shown in FIG. 3.
  • starting pulse generator 152 sequential control device 156 and signal controls 162, 172 have not been shown, these elements are all well known to those skilled in the art and could be implemented in any number of specific circuits or combination of circuits to operate with the display device embodying the present invention.
  • FIGS. 3, 4 and 5 the operation of a preferred embodiment to display representative alphanumeric symbols, B K, as shown in FIG. 5, will be described.
  • a negative pulse voltage of approximately 250 volts is generated by start pulse generator 152 and applied to start cathode element 108 by line 132.
  • This start pulse causes the gas plasma in the region of start cathode element 108 to ionize due to the field created between the start cathode element 108 at 250 volts and the anode grid structure 1 14 at approximately volts.
  • start pulse generator 152 switches the voltage applied to start cathode 108 to a more positive value, such as -150 volts and sequence control 156 activates lines 134 applying --250 volts to cathode elements C1, C4, C7, etc. Since cathode element C1 is immediately adjacent to start cathode element 108, the localized gas plasma moves stepwise from the region of start cathode 108 to the region of cathode element C1.
  • phase 2 is activated by sequence control 156 causing a 250 volt signal to appear on lines 136 and a more positive voltage to appear on lines 134, thereby deactivating cathode elements C1, C4, C7, etc. and causing the localized discharge to move from cathode element C1 to cathode element C2.
  • phase 2 is turned off, that is, returned to a more positive potential and phase three is activated; that is, sequence control 156 applies a 250 volt signal to lines 138 while maintaining lines 134 and 136 at a more positive potential.
  • sequence control 156 applies a 250 volt signal to lines 138 while maintaining lines 134 and 136 at a more positive potential.
  • the localized discharge then is transferred from cathode element C2 to cathode element C3 and the combination of signal voltages on R1 through R,, then cause the third column of points to be illuminated in the alphanumeric character B.
  • sequence control 156 steps from phase 1 to phase 2 to phase 3 during a single scan of the entire display area. Scanning of the entire display is repeated at a rate such as 30 or times a second to avoid any noticeable flicker to the human observer.
  • the points to be illuminated on the face of the display device are controlled by the coincidence of signal voltages appearing on lines 1 18 at the appropriate row R,, and cathode elements C activated by the appropriate phase voltage.
  • a signal voltage of approximately 6-10 volts is applied to these rows R which are to be activated, and a zero potential is applied to those rows R,, which are to be inactive.
  • Signal voltages applied to columns R may be varied in an alalog or digital fashion corresponding to variations in intensity to achieve gray scale rendition.
  • the alphanumeric characters B, K indicate a character block of five cathode elements in the horizontal direction by seven rows in the vertical direction with a space of one cathode element appearing between each character.
  • phase 3 which would normally activate cathode element C6
  • none of the row elements 118 are activated, thereby resulting in no illumination at that column on the phosphor.
  • COLOR To generate a multicolor display, a plurality of phosphor strips, each for emitting a different color light is deposited over conducting strips 118 on support plate 126 rather than a single monochrome phosphor as described above.
  • sequence control 156 controls application of phase 1, 2 and 3 signals representative of three primary colors, such as, red, green and blue.
  • phase 1 When, for example, phase 1 is activated C, will support ionization of a gas plasma which results in electrons striking a red emitting phosphor strip causing a red light output at that instant of time.
  • electrons striking other phosphor strips will produce light output of different color.
  • a structure embodying the present invention could be extended in the horizontal and vertical direction to produce a complete large screen display device having as many separate rows of characters with many characters in each row with limitations only in the technology in constructing the cathode element and the transparent conducting strips 118.
  • gray scale rendition may be achieved by varying the potential applied to lines 118 in an analog or digital manner between 0 and some positive potential.
  • a device for displaying information comprising:
  • each of said cathode elements being connected to one of a plurality of stepping voltage sources;
  • anode structure placed within said transparent envelope and adjacent said plurality of cathode elements, said anode structure being connected to a fixed potential
  • a transparent carrier mounted between said anode structure and the front plate of said transparent envelope; a plurality of closely spaced parallel transparent signal conductor strips at right angles to said cathode elements, deposited on one face of said transparent carrier, and a layer of phosphor depositedpver the carrier which is capable of emitting light when impacted by electrons, the
  • a display device for displaying alphanumeric information comprising:
  • transparent carrier having a plurality of linear conductors mounted on one face of said carrier, said conductors carrying a signal voltage to a row of elements to be displayed, and a layer of phosphor deposited over the carrier and conductors a plurality of anode elements contained in said transparent envelope and adjacent to and space from the layer of phosphor each of said anode elements being connected to a fixed potential, said anode elements accelerating electrons to said phosphor layer;
  • each of said cathode elements perpendicular to said linear conductors and connected to one of a plurality of control devices, said control devices controlling the potentials applied to groups of said cathode elements, wherein on a coincidence of an activating potential applied to a cathode element, and a signal voltage applied to one of said conductors, electrons emitted by said cathode element and accelerated by said anode elements, strike said phosphor layer causing light to be emitted.
  • a display device according to claim 3 wherein said phosphor layer is ZnO.
  • a display device according to claim 3 wherein said phosphor layer is a conducting material.
  • a display device according to claim 1 wherein said gas is an inert gas.
  • said phosphor layer comprises a plurality of sets of strips of phosphor wherein each of said sets of strips of phosphor emits light of a different color to produce a colored information display.
  • a display device wherein said signal voltage is varied to display information in a gray scale rendition.

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  • Gas-Filled Discharge Tubes (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
US00157971A 1971-06-29 1971-06-29 Self-scanning plasma display device with phosphor screen Expired - Lifetime US3725731A (en)

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US15797171A 1971-06-29 1971-06-29

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US (1) US3725731A (enExample)
JP (1) JPS5443871B1 (enExample)
DE (1) DE2222907A1 (enExample)
FR (1) FR2143708B1 (enExample)
GB (1) GB1360356A (enExample)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3866090A (en) * 1972-10-31 1975-02-11 Philips Corp Gas discharge panel and operating system
US3961217A (en) * 1975-02-24 1976-06-01 Burroughs Corporation Gaseous discharge display panel having two color bar display
US4566006A (en) * 1982-05-17 1986-01-21 Hitachi, Ltd. Gas discharge display apparatus
US5872541A (en) * 1987-07-15 1999-02-16 Canon Kabushiki Kaisha Method for displaying images with electron emitting device

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2926393C2 (de) * 1979-06-29 1982-10-07 Siemens AG, 1000 Berlin und 8000 München Gasentladungsanzeigevorrichtung
GB2235819A (en) * 1989-08-12 1991-03-13 Cathodeon Ltd Gas discharge display device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3262010A (en) * 1960-08-31 1966-07-19 Hughes Aircraft Co Electrical display apparatus incorpolrating electroluminescent and gas discharge devices
US3499167A (en) * 1967-11-24 1970-03-03 Owens Illinois Inc Gas discharge display memory device and method of operating
US3603836A (en) * 1969-04-02 1971-09-07 John D Grier Conductor configurations for discharge panels

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3262010A (en) * 1960-08-31 1966-07-19 Hughes Aircraft Co Electrical display apparatus incorpolrating electroluminescent and gas discharge devices
US3499167A (en) * 1967-11-24 1970-03-03 Owens Illinois Inc Gas discharge display memory device and method of operating
US3603836A (en) * 1969-04-02 1971-09-07 John D Grier Conductor configurations for discharge panels

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3866090A (en) * 1972-10-31 1975-02-11 Philips Corp Gas discharge panel and operating system
US3961217A (en) * 1975-02-24 1976-06-01 Burroughs Corporation Gaseous discharge display panel having two color bar display
US4566006A (en) * 1982-05-17 1986-01-21 Hitachi, Ltd. Gas discharge display apparatus
US5872541A (en) * 1987-07-15 1999-02-16 Canon Kabushiki Kaisha Method for displaying images with electron emitting device

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Publication number Publication date
JPS5443871B1 (enExample) 1979-12-22
DE2222907A1 (de) 1973-01-18
FR2143708B1 (enExample) 1974-07-26
GB1360356A (en) 1974-07-17
FR2143708A1 (enExample) 1973-02-09

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